Actuating mechanism for radio condensers



Dec. 9, 1947. Y I 2,432,418

ACTUATING MECHANISM FOR RADIO CONDENSERS Filed Aug. 50, 19 14 I INVENTOR. LOUIS HEGY BY r ATTORNEY.

Patented Dec. 9, 1947 UNITED STAT ACTUATING lVIECHANISM FOR RADIO CONDENSERS;

Louis Heg'mBurbank, Calif., assignor to .Bendix Aviation Corporation, South Bend, 1nd,; acorporation of Pelaware o App i ation. Au ust 30, 1944, S i NO.- 5 11 8 7 Claims. 1

This invention relates to mechanisms for automatically :controlling. the rotation of a shaft exao'tly intopredetermined angular positions and is particularly useful 'forremote control of variable 1c oknclez sers usedto tune radiol circuits and the 1e..... Anobject of the invention is to provide an actuatingmeohanisrn of the type referred to which converts. rotation of an input or driving. shaft intotintermittent rotation of an outpu t or driven and'holds Iatteriin exact predetermined eeqierrg itwns hil Ti is. at t bi t W re haft-.eenbasierWsi a any a t i agathering: ra efi an l r movmem wrhout 'mpairingthe accuracy of positioning of the q. ve s it i1 a M I dno ther object is to provide an actuating mechanism o for converting. successive approxi mate ly equal angular movements of a driving shaft into intermittent; accurately measured unegual angular movements of a driven shaft] Still another object is to provide an actuating mechanism-of the type described in the precedin Paragraph in which the positions of rest of the driven shaft can be readily adjusted. at

Qther more specific objects and features of. the inventionwill becomeapparent from the detailed descriptign-to-follow of one embodiment of the l llfi fi lr Ir1; i;ts -simplest form; the invention comprises a; rank; pin on a driving shaft which is adapted in -response to'rotation of the driving shaft to intercept and rock an arm on a parallel driven shaft, in which the armis curved with the same radius pf curvature as the radius of revolution of the crank -pin, so that after thecrank pin has rocked'the arm into a predetermined position it thereafter slides along the arm without movingit-further. In addition, a springmechanism holdsthe, arm against the crank pin-so that movement of the driven shaft out of the predetermined position by extraneous forces is prevented.

In a more practical-form, the invention comprises-a plurality of angularly and axially spaced crank-pins on thedriving shaft cooperating with a plurality of angularlyand axially spaced arms on; the driven shaft, so that approximate rotation of thedrivingshaft into predetermined angular; positionsrotates the driven shaft exactly into predetermined angular positions.

-In the drawing: Fig; 1 is an end viewof an actuating mechanism. --1n: d n e w t the n ention. 7

Fi 21s a v a r t ans estoifia llQQkiP-E. intbetdirectionni'thearrow I 0. Fiat;

. 'Fig. 3 is a section takenalong the line IIL-III of Fig. 2."

Fig.4 is a detail section taken along the line rv-1v of Fig. 2. q

f'Fig. 5 is an end view of a variable condenser that may be actuatdby the driven shaft of the mechanism shown in Figs. lto 4, and;

Big. Gris a'sche'matic diagram showing a circuit that may be employed forremote control of the'mechanism.f

Referring first to Fig. 2,"th ere is'disclosed a structure comprising a pair of parallel, spaced apart,v frame plates Ill and l I, respectively, which are mutually supported from each other by a pluralityflof pillars "l2; these pillars being secured to the. frameplatesby screws,|3 (Fig. 1)

'matelyf into anyone of aplurality of positions,

hiya control circuit to bedesc'ribed later. Rigidlyi secured to the driving shaft l4 intermediate the frameplates I0 and II are a plural ityof ld'isks lii to 24 inclusive which are spaced apart by aplurality of wasl ers 25. The washers and. disks may be pressed on, to the shaft l4 or rigidly secured thereto in any desired manner. Supported by the successive pairs of adjacent disks area plurality of crank pins 26, 21, 28, 29, 30, and 3| respectively). Successive pins being equally angularly spaced from each other at intervals in the particular embodiment shown. ..'I he' driven shaft l5 hasmou'nted thereon, between the frame plates l0 and. l I, a plurality of arms 26a, 2,'la 2 8a, 29a, 30a, and 3la respectively;

each being axially juxtaposed to the crank pin bearing the corresponding .reference numerals. The arms 26a to 31a inclusive are spaced apart along thef'shaftfi byspacing washers 35, the lowermost of which rests "against a shoulder 36 (Fig. if-on the shaft; I5,. and the uppermost of which bears. against a'starwheel 31 having a flange 38,.which' is threaded on to the upper end of shaft l5. The fiange38is journaled in an upperbearing 39 mounted in an aperture proyidedftherefor in the upper frame plate In. The lower endof shaft 15 is directly journaled in a bearing 40 in the lower frame plate II. The

sta It treatm nt grai spacer washers 35 have tongues fitting in the keyway so that they are non-rotatable with respect to the shaft [5. However, the arms 26a to 31a have circular apertures through which the shaft extends, so that they are angularly adjustable on the shaft. Such adjustment can be readily effected by slightly loosening the starwheel 31, while the shaft [5 is restricted against rotation by a screw driver inserted in a slot 32 in the upper end thereof, and then moving one or more of the arms 26a to 3 la inclusive into desired positions, after which the arms are locked securely in place by tightening the starwheel 37.

In operation, the drivingshaft I4 is rotated by the motor into any one of six different positions spaced apart approximately 60. In each one of the six positions, one of the crank pins 26 to 3| inclusive will lie against one of the arms 26a to 3la inclusive, and the edge of each arm that is contacted by its associated crank pin is arcuate and its center of curvature is coincident with the axis of the driving shaft I4, so that the arm remains in exactly the same angular position while its associated pin slides along its arcuate edge. Thus, in Fig. 3 the crank pin 26 is lying against the arcuate surface of the arm 26a, and the pin 26 can rock through a substantial angle in either direction without shifting the arm 26a. As a result, it is only necessary that the driving shaft 54 be stopped approximately at the desired position for the driven shaft I5 to be exactly located in a desired position.

It is desirable to hold each arm against its asso ciated crank pin, and to this end I provide a holding mechanism that is actuated by that one of the crank pins next in advance of the crank pin that is engaging one of the arms on the driven shaft. This holding mechanism, as shown in the drawing, comprises a plate 44 having one edge juxtaposed to contact which ever one of the arms 23a to 3 l a inclusive happens to be engaged by one of the crank pins 26 to 3| inclusive. Adjacent its opposite edge, the plate 44 is welded or otherwise secured to the ends of a plurality of spring wire elements 45, which extend through a rock shaft 58, which is pivoted at opposite ends in the frame plates l9 and H. The other ends of the wire elements 45 are aligned axially with different ones of the crank pins 26 to 3| inclusive, and the outer portions of the wires are preferably, although not necessarily, curved to hav a radius of curvature equal to the radius of revolution of the crank plIlS.

It will be observed that in the position shown in Fig. 3 the outer end of one of the wires 45 is engaged by the crank pin 3!, which is next in advance of the crank pin 26. As the pins moved into the position shown, pin 3] first rocked the plate 44 against the rear edge of the arm 26a and thereafter deflected the wire element 45 that it had contacted, to resiliently press the plate d4 against the arm 26a and hold it firmly against crank pin 26, so that there can be no tendency for the driven shaft I5 to rock in counterclockwise direction. If it is desired to move the driven shaft into a'second position in which another of the arms 27a to am is moved into the angular position occupied by arm 26a in Fig. 3, the shaft i5 is rotated clockwise approximately into such posi-' tion that the said other pin approximately occupies the position pin 26 occupies in Fig. 3. Initial movement of the shaft M out of the position shown will first carry pin 26 beyond the end of arm 26a and carrypin 3| beyond the wire element 45 that it was contacting; thereafter the next arm, 27a in this instance, will be engaged by the pin 2'? and carried into the position previously occupied by arm 26a. At the same time crank pin 26 will engage one of the wire elements 45 and rock the plate 46, to hold the arm 21a against the pin 27. The driving shaft Hi can then be stopped or it can continue to rotate until some other desired one of the arms is engaged and moved into position of rest by its associated crank pin.

It will be observed that it is not essential that the different crank arms 23a to 3m inclusive be angularly spaced equal distances apart. However, there is a minimum angular spacing that must be maintained between successive arms; otherwise the holding plate 44 will strike against the end of the preceding arm.

It is also obvious that the angular spacing between the successive arms cannot be too great else the next arm to be engaged will lie outside the path of revolution of its associated crank pin.

However, there is a very substantial range of adjustment that is possible with the arrangement shown, and where the device is employed to actuate a radio tuning condenser, it is usually possible to so adjust the arms as to select six desired stations lying within the tuning band of the condenser.

Where two stations are located so close together that the angular distance through which the tuning condenser must be rotated is less than the minimum permissible angle between successive arms on the shaft 15, one of the stations can be tuned to by employing a condenser having semi-circular rotor plates 59 and semi-circular stator plates 5| as shown in Fig. 5. With such a condenser there are two positions for each capacity value, and one of the two positions is usually spaced far enough from the positions corresponding to other stations to avoid interference by the holding plate 44.

One remote control circuit that may be employed with the structure shown is illustrated in Fig. 6. It will be observed that the motor I1 is connected in series between ground and one terminal of a battery 68, and the other terminal of the battery is connected through an automatic switch mechanism 6|, a plurality of leads62 and a manual control switch 63 back to the ground. The switch 6| is built into the mechanism and as shown in Figs. 1 and 2, comprises a conductive disk fi l mounted on the shaft M for rotation therewith, and a plurality of equally spaced contacts 65, 66, 61, B8, 69, and 18. A master contact '1! is in contact with the disk 64 at all times. The disk 64 has a notch 12 therein which notch successively breaks contact between the disk 64 and the contact 65 to Til inclusive during rotation of the shaft M.

It will be observed from Fig. 6'that if the switch 53 is moved to any new position, it will complete a circuit through one of the contacts 65 to it, the disk 64, and the master contact ll, through the battery 86 and the motor l1, causing the'latter to run and rotate the shaft [6. The motor will continue to run until the notch 12 reaches that one of the contacts 65 to 19 which is grounded by the switch 63, whereupon the motor will stop. The motor will not stop instantly, so the position of rest of the shaft it will not be accurately determined. The great advantage of the present system is that accurate stopping of the shaft HA is not necessary. It may be desirable to employ some known expedient for decelerating the motor when the current is cut ofi, but in the great majority of cases, the most that is necessary is some form of dynamic braking of the motor such as may be achieved by using a motor having a permanent magnetic field and a relay connected-in the energizing circuit of the motor for short circuiting the brushes when the current is out off. Such expedients are well known.

Although for the purpose of explaining the invention one embodiment thereof has been disclosed and described in substantial detail, various departures from the exact structures shown can be made while still utilizing the advantages of the invention, and the invention is to be limited only to the extent set forth in the appended claims.

I claim:

1. A mechanism for exactly positioning a driven shaft in response to approximate positioning of a parallel driving shaft comprising: first crank means adapted to be revolved with said driving shaft; arm means connected to and projecting from said driven shaft into the path of revolution of said first crank means; said arm means having an arcuate surfac intercepted by said first crank means, said arcuate surface being of the same radius as the radius of revolution of said first crank means, and the spacing between the axes of said driving and driven shafts being such that the center of curvature of said arcuate surface is coincident with the axis of said driving shaft in one angular position of said driven shaft.

2. A mechanism for exactly positioning a driven shaft in response to approximate positioning of a parallel driving shaft comprising: first crank means adapted to be revolved with said driving shaft; arm means connected to and projecting from said driven shaft into the path of revolution of said first crank means; said arm means having an arcuate surface intercepted by said first crank means, said arcuate surface being of the same radius as the radius of revolution of said first crank means, and the spacing between the axes of said driving and driven shafts being such that the center of curvature of said arcuate surface is coincident with the axis of said driving shaft in one angular position of said driven shaft; and means actuated from said driving shaft for urging said arm against said first crank means during at least a portion of the range of movement of said first crank means along the arcuate surface of said arm means.

3. A mechanism for exactly positioning a driven shaft in response to approximate positioning of a parallel driving shaft comprising: first crank means adapted to be revolved with said driving shaft; arm means connected to and projecting from said driven shaft into the path of revolution of said first crank means; said arm means having an arcuate surface intercepted by said first crank means, said arcuate surface being of the same radius as the radius of revolution of said first crank means, and the spacing between the axes of said driving and driven shafts being such that the center of curvature of said arcuate surface is coincident with the axis of said driving shaft in one angular position of said driven' shaft; second crank means fixed relative to said first crank means for revolution therewith; and means actuated by said second crank means for urging said arm against said first crank means during at least a portion of the range of movement of said first crank means along the arcuate surface of said arm.

4. A mechanism for exactly positioning a driven shaft in response to approximate positioning of a parallel driving shaft comprising: crank means adapted tobe revolved with said driving shaft; arm means connected to and projecting from said driven shaft into the path of revolution of said crank means; said arm means having an arcuate surface intercepted by said crank means, said arcuate surface being of the same radius as the radius-of revolution of said crank means, and the spacing between the axes of said driving and driven shafts being such that the center of curvature of said arcuate surface is coincident with the axis of -said driving shaft in one angular position of said driven shaft; second crank means revolved with said driving shaft; resilient lever means fulcrumed for oscillation and having one end oscillatable toward and away from the side of said arm means opposite the arcuate surface thereof and having its other end extending into the path of said second crank means when said first crank means is contacting said arcuate surface, whereby said second crank means engages said other end of said lever means and urges said one end against said arm means to hold the arm means against said first crank means.

5. A mechanism for positioning a driven shaft in a plurality of different angular positions in response to positioning of a parallel driving shaft in a plurality of corresponding positions, said mechanism comprising: a plurality of angularly spaced crank means adapted to be revolved by said driving shaft, said crank means being spaced axially from each other; and a plurality of axially spaced arm means connected to and projecting from said driven shaft into the paths of revolution of different ones of said crank means; in which said driven shaft is of circular cross section with a depressed axially extending keyway, said arm means having circular apertures through which said driven shaft extends, whereby said arm means are rotatable with respect to th shaft, separating washers on said shaft between which said arms are interleaved, said washers having keys extending into said keyway whereby they are non-rotatable with respect to said shaft, and means for longitudinally compressing said washers and arms together and frictionally locking said arms to said shaft for rotation therewith in desired positions of angular adjustment.

6. A mechanism for positioning a driven shaft in a plurality of different angular positions in response to positioning of a parallel driving shaft in a plurality of corresponding positions, said mechanism comprising: a plurality of angularly spaced crank means adapted to be revolved by said driving shaft, said crank means being spaced axially from each other; a plurality of axially spaced arm means connected to and projecting from said driven shaft into the paths of revolution of different ones of said crank means; each of said arm means having an arcuate surface of the same radius as the radius of revolution of its associated crank means and the spacing between the axes of said driving and driven shafts being such that the center of curvature of thearcuate surface of each arm means is coincident with the axis of said driving shaft in .a different angular position of said driven shaft.

7. A mechanism as described in claim 6 including a plurality of parallel spaced disks on said driven shaft, each pair of adjacent disks supporting a pin extending therebetween, said pins constituting said crank means, and means for urging each arm against its associated crank means during at least a portion of the range of movement of said crank means along the arcuate surface of the arm, comprising lever means having a fulcrum axis parallel to said shafts, said lever means being axially continues at one end and being movable into the paths of all of said arms and being axially discontinuous at the other end to form separate fingers, each movable between a different pair of said disks into Contact with the crank pin between that pair of disks.

LOUIS HEGY.

REFERENCES CITED The following references are of record in the file of this patent:

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